1. Field of the Invention
The present invention relates to a differential limiting apparatus for a differential included in an all-terrain vehicle.
2. Description of the Related Art
A vehicle with a differential is provided with a differential locking device as a differential limiting apparatus in order to limit the difference in angular speed between the two output shafts of the differential. The differential locking device interlocks the two output shafts by a dog interlocking system or a spline interlocking system.
A conventional straddle-type four-wheeled all-terrain vehicle is provided with a differential locking device of the dog interlocking system operated by a differential locking device operating mechanism disposed at a position beside an engine and near the rider""s foot. Referring to FIG. 9 showing the conventional differential locking device operating mechanism 160 for operating the differential locking device of the dog interlocking system, a differential locking case 164 supporting a differential locking lever 161 is disposed beside the engine 105. The differential locking lever 161 is turned in the direction of the arrow T2 from an unlocking position indicated by imaginary lines to a locking position indicated by continuous lines to slacken a differential locking device operating cable 162 so that the differential is locked. The differential locking lever 161 is biased in the direction of the arrow G by a return spring 167. The return spring 167 turns between positions on the opposite sides of a pivot 166 supporting the differential locking lever 161 across the pivot 166, so that the differential locking lever 161 can be held at either the locking position or the unlocking position.
Another all-terrain vehicle is provided with a differential limiting apparatus capable of producing a differential limiting torque by using, for example, coned disk springs.
The differential locking device of the dog interlocking system is capable of only locking or unlocking the differential regardless of the difference between loads on the right and the left wheel of the all-terrain vehicle and is incapable of operationally adjusting the magnitude of differential limiting torque while the vehicle is traveling. A locking operation for locking the differential by the differential locking device takes much time to engage the dogs of the differential locking device.
The differential locking device operating mechanism 160 disposed at the position beside the engine 105 and near the rider""s foot requires the rider to remove a hand from a handgrip attached to a handlebar and to operate the differential locking lever 161 disposed at the rider""s foot in a slightly bent position. Thus, the rider is unable to remain in a riding position for a moment and to perform the differential locking operation quickly.
The aforesaid differential limiting apparatus provided with the coned disk springs for continuously producing a fixed differential limiting torque has a fixed differential limiting torque transmitting capacity and is incapable of varying the differential limiting torque according to the condition of travel or turning of the all-terrain vehicle while the all-terrain vehicle is traveling.
Accordingly, it is an object of the present invention to provide a differential limiting apparatus for an all-terrain vehicle capable of producing a desired differential limiting torque according to the difference in load between right and left wheels of the all-terrain vehicle even while the all-terrain vehicle is traveling, of enabling a rider to perform a differential torque changing operation in an ordinary riding position, and of maintaining a predetermined maximum differential limiting torque.
According to the present invention, a differential limiting apparatus for a differential of an all-terrain vehicle, comprises: a differential limiting mechanism of producing a changeable differential limiting torque, a differential limiting mechanism operating lever disposed so as to be operated and turned by a hand gripping a handgrip attached to a handlebar of the all-terrain vehicle and interlocked with the differential limiting mechanism so that the differential limiting torque varies according to an angle through which the differential limiting mechanism operating lever is turned; and a lever stopping mechanism for stopping the differential limiting mechanism operating lever at an angular position for producing a predetermined maximum differential limiting torque.
A rider riding the all-terrain vehicle is able to produce a desired differential limiting torque without removing the hand from the handgrip. The differential limiting lever turned to the angular position for producing the predetermined maximum differential limiting torque can be stopped at the same angular position to maintain the predetermined maximum differential limiting torque. The interference of the differential limiting mechanism operating lever with the handgrip and the handlebar can be prevented.
Preferably, the lever stopping mechanism includes a projection formed integrally with the differential limiting mechanism operating lever, and a stopping surface formed on a lever holder by which the differential limiting mechanism operating lever is held on the handlebar. The stopping surface comes to engage with the projection to stop the differential limiting mechanism operating lever at the angular position for producing the predetermined maximum differential limiting torque.
The operating lever mechanism can be readily mounted on the handlebar.
Preferably, the differential limiting mechanism operating lever is supported on the lever holder which also supports a brake lever of the all-terrain vehicle.
Increase in the number of parts of the all-terrain vehicle by the equipment of the differential limiting apparatus can be limited to the least necessary extent and assembling work can be simplified.